Skip to Main Content

As scientists try to track the spread of a new, more infectious coronavirus variant around the world — finding more cases in the United States and elsewhere this week — they are also keeping an eye on a different mutation with potentially greater implications for how well Covid-19 vaccines work.

The mutation, identified in a variant first seen in South Africa and separately seen in another variant in Brazil, changes a part of the virus that your immune system’s antibodies get trained to recognize after you’ve been infected or vaccinated. Lab studies show that the change could make people’s antibodies less effective at neutralizing the virus. The mutation seems to help the virus disguise part of its signature appearance, so the pathogen might have an easier time slipping past immune protection.


It’s not that the mutation will render existing vaccines useless, scientists stress. The vaccines authorized so far and those in development produce what’s called a polyclonal response, generating numerous antibodies that home in on different parts of the virus. Changes to any of those target sites raise the possibility that the vaccines would be less effective, not that they won’t work at all.

“With one mutation or even three mutations, it’s expected the antibodies will still recognize this variant, though they might not recognize it as well as other variants,” said Ramón Lorenzo-Redondo, a molecular virologist at Northwestern University’s Feinberg School of Medicine.

Essentially, the mutation is getting attention because it appears more likely to have some effect on vaccines than other mutations that have emerged, though scientists are still trying to test that hypothesis. The more contagious variant raising global alarms, which was first seen in the United Kingdom and is referred to as B.1.1.7, is not thought to have mutations that will greatly affect vaccines, the evidence so far indicates.


“We need to be monitoring for these mutations,” said Jesse Bloom, an evolutionary virologist at Fred Hutchinson Cancer Research Center, who with colleagues published a paper about this specific mutation, known as E484K, this week.

But Bloom added that he believed the virus would have to pick up multiple mutations — and particular mutations in specific spots, not just any alterations — to have a serious effect on vaccine efficacy, which will likely take some time.

“I’m quite optimistic that even with these mutations, immunity is not going to suddenly fail on us,” Bloom said. “It might be gradually eroded, but it’s not going to fail on us, at least in the short term.”

Scientists do think the coronavirus could eventually change so much that the immunity provided by vaccines will be threatened, a process that will pick up as the number of people protected from the virus — either through vaccination or infection — grows and evolutionary pressure in turn increases. But they still anticipate it could take years, and that when it does occur, vaccine makers can tweak their designs to match the newer variant, a process some companies have said would only take weeks.

The SARS-CoV-2 coronavirus, which causes Covid-19, has been mutating as it spreads, just like other viruses. Many of the mutations do nothing, and some might even impede the virus’s quest to replicate and spread. But every so often, a random mutation gives the virus an evolutionary advantage, and that variant can then become dominant. Early on in the pandemic, a mutation known as D614G helped the coronavirus spread more easily, and variants with that mutation quickly overtook others globally.

B.1.1.7, which has since spread to other parts of the world, appears to be even more infectious, with some estimates saying it’s 50% more transmissible. One of its mutations, called N501Y, improves how well the virus’ spike protein can attach to a receptor called ACE2 on human cells, making it more likely for the virus to successfully infect cells and for the virus to pass from person to person.

The same N501Y mutation is also present in the variant identified in South Africa, though the two variants evolved independently. (Public health authorities are trying to steer people away from using terms like the “U.K. variant” or “South African variant,” just as they discourage people from tying SARS-2 by name to China or Wuhan. “We need to use the names appropriately because we don’t want to stigmatize where these variants have been identified,” the World Health Organization’s Maria Van Kerkhove said Tuesday. “That’s true for any virus that’s identified.”)

The inclusion of N501Y appears to help the variant in South Africa spread faster as well, but the variant also has the E484K mutation, unlike the variant that first appeared in the U.K. Though mutations in the same part of the virus have cropped up previously during the pandemic, the specific E484K mutation is attracting more interest now in part because it’s in this variant that’s spreading across South Africa and, through travelers, has started to appear elsewhere, including Japan, Norway, and the U.K.

The E484K change occurs on a part of the spike protein called the receptor binding domain, which plays a crucial role as the virus attaches to ACE2 and is a key target for antibodies. As lab studies have shown, antibodies don’t recognize variants with E484K as well as other forms.

Research from Bloom and colleagues this week further added to that evidence. In their study, which involved mapping how antibodies from people who had recovered from Covid-19 fared against different variants, the scientists found that mutations like E484K had the biggest impact on antibodies’ ability to block the virus, with some people experiencing a more than 10-fold drop in neutralization against the variant. The researchers called the location of the E484K mutation “the site of most concern for viral mutations.” (There was variability among the samples, however; some people were able to neutralize the variant just fine, and mutations in other places had more of an impact than E484K did for certain people.)

Bloom’s study was focused on people who had recovered from an infection, not those who had been vaccinated; researchers around the world are investigating how well current vaccines stand up to different variants.

But despite what he and colleagues found about E484K, Bloom noted that the mutation only reduced neutralizing activity, and didn’t eliminate it. Current vaccines, meanwhile, have shown they can generate strong immune responses. “I’m confident current vaccines will be useful for quite a while,” Bloom wrote in a Twitter thread detailing the research.

The more pressing concern for now, scientists say, remains the spread of B.1.1.7, the variant first seen in the U.K. Though it’s not thought to cause more severe cases of Covid-19, if it causes more cases overall because it spreads more easily, that will lead to more hospitalizations and deaths. It is also likely harder to control than other variants and raises the threshold of the percentage of the population that needs to be protected to reach herd immunity.

“The variant is a really big deal,” said Marc Lipsitch, an epidemiologist at Harvard’s T.H. Chan School of Public Health.

Lipsitch said the U.S. should focus its efforts on curtailing the variant, including by sequencing more samples from patients to identify cases and directing its contact tracing and quarantining campaigns to try to hem it in.

“To the extent that we can find those and preferentially stop the spread, it won’t be perfect, it will be far from perfect, but anything we can do to delay the spread of this new variant virus will make control easier and will help us in the race to get more people vaccinated before this becomes more common,” he said.

  • Trump was the main propagator of the “China Virus” & he was obviously politicizing the name. Now that the scientific community has agreed on a name, let’s just use that.
    1. Yes, that’s why they are/will be banned. Note that they also exist in other countries, but usually only sell marine products, not bats, pangolins etc.
    2. Capitalist supply & demand. Corrupt officials exist almost everywhere, unfortunately.
    3. The doctor just died of COVID, sadly. Public health cover-ups are never good (look at Florida & the Trump admins pressuring the CDC & Trump himself downplaying the danger).
    Animals are mostly eaten in China for food, not because they are aphrodisiacs. Meat eating is also not restricted to China. The source of SARS-1 has not been identified, it’s just assumed that it came from wild animals, but through what route is unknown. (as SARS-COV-2). The “Spanish Flu” (from birds) is believed to have originated in the U.S. as was the H1N1 flu epidemic (from pigs). Even if we all gave up eating any warm-blooded animals, the chance of viral diseases would be reduced, not eliminated. Most people are not virologists, & so can’t really be blamed for not supporting measures to curb the spread of disease until now.
    The cost if supporting the WHO is much less than each nation creating it’s own equivalent organisation, in addition there would be much less international cooperation.

  • We all know as bd must admit that compared to ted up other countries that have had some successes succeeded in curtailing the spread (e.g., New Zealand, Taiwan, Singapore, South Korea) that has been able successfully to control the pandemic somewhat, US simply is losing control due largely IMO inability to curtail the pathetic sense of personal liberty and individual freedom. Another fatal flaw is inability to implement a rigorous and air tight contact tracing.
    So how is it possible for the US to find dangerous variants, sequence them thoroughly and quickky, enforce mandatory contact tracing then hopefully be able to establish and execute a robust public health policy to “ptltefetentially stop the spread”?

    It is simply not feasible nor possible
    with our pig headed stubbornness and warped culture.

  • #1 im a Frontline nurse.
    #2 if she’s working with covid pt, her gown is backwards and insufficient ppe for direct covid care, not wearing goggles or shield. Shes spewing and spreading germs like crazy!!

  • This sounds like the flu type of vaccine eh? A guessing game every year for effectiveness? I know this is not a live vaccine, but this is the first time its actually used on humans even though the “science” has been around and tested on animals.
    Its a personal choice if you want to take it or not, I won’t judge you if you take it. But don’t judge me if I don’t… I have never understood if something is “Safe and Effective” aka from every pharma brochure, and talking point for news, and it requires that everyone take it to be completely immune. That makes no logical sense.

    • You don’t need to understand it, you just need to get the shot. When they say “safe” they mean it’s not likely to kill you or cause long-term damage. There is always an exception as far as reactions go, but anything serious would make it a bad vaccine. As for these new ones, some things are unknown, but we do know that Covid-19 can kill you or cause long-term damage, while effectiveness of the vaccine means you bypass actually catching Covid-19 and avoid those issues. So, even if there might be some small risk of allergies from the vaccine, catching Covid-19 is very likely to be worse. A vaccine doesn’t give you the disease, it gives your immune system a “scent” of it, much like giving a dog a piece of cloth to sniff so they can find the bad guy that wore it. There are some vaccines that are “live” but the Covid-19 vaccine definitely isn’t one of them.

  • If you’re reading this, probably don’t need a reminder to please mask and do social distancing.
    Yet another analogy is (often invisible) fire spreading through tinder. If you don’t want houses burning down then fire-breaks help!
    If you do want houses burning down then go get help.

  • We may end up needing more than one vaccine, or a hybrid vaccine. I think that ultimately, though, there are only a certain number of these mutation sites like E484K, not an endless number of them.

    • As vaccine-resistant strains broaden and proliferate, any one vaccine that encodes one spike is going to stimulate lots more antibodies that are non-neutralizing for the viruses not covered by that vaccine. With so many non-neutralizing antibodies, there is an increased risk of vaccine-enhanced disease as well as triggering autoimmunity.

      One of the factors that will likely further accelerate the emergence of vaccine-resistant strains is the roll-out of 2-shot vaccines in the middle of a pandemic running at unprecedented levels. People will catch COVID between their shots and expose the virus to low titers of neutralizing antibodies, which creates selection pressure that favours vaccine-resistant mutations.

      I fully expect that by the time 50 million Americans are vaccinated, the dominant strain will be vaccine resistant, and will cause enhanced disease.

      The multi-strain problem is less severe with influenza because it is far less likely to cause ADE or VAERD or autoimmunity. But SARS-CoV-2 has these nasty potentials than need to be planned for in the design of the vaccine and other responses.

      Sadly. as we’ve seen throughout the pandemic response, nobody’s going to bother with any of this until after it’s too late.

Comments are closed.